Compositions for decontamination, disinfection and sterilization must have excellent microbicidal efficacy (ME) and be non-corrosive. It is also generally desirable that the composition act rapidly. For the treatment of objects and surfaces, it is further desirable that good ME be achieved with minimal quantities of the composition. For surfaces, this means the application volume is relatively low, i.e., a small volume covers a large surface. In addition, the use of compositions that act with a variety of microbicidal mechanisms offers less likelihood of leading to the evolution of organisms that are resistant to disinfection. Decontaminant, disinfectant and sterilant compositions that act with ‘dark’ chemistry and also with light-activated ‘photochemistry’ offer such multiple ‘kill’ mechanisms.
Spores are generally regarded as more difficult to kill than vegetative bacteria and viruses. However, because of their smaller size, viruses can be located in pores and crevices and thereby evade contact with decontaminants, disinfectants and sterilants, which do not penetrate well into such spaces. Moreover, the wetting of the microbe to be killed by the decontaminant, disinfectant or sterilant aids the mass-transfer and contact of the lethal chemical species with the target loci of the microbe and its biochemical components. Thus, another key attribute of the disinfectant and/or sterilant is that it has good rheological properties. Such properties affect the application of the composition and also its ME.
Compositions containing peroxide, especially hydrogen peroxide (HP), and one or more peracids, especially peracetic acid (also called peroxyacetic acid, PAA) have been proven to be very effective sporicides, bactericides, and virucides. Many such preparations have passed the necessary tests and are registered products as sanitizers, disinfectants, and sporicides. A few are also products registered as sterilants. Many of these peroxide/peracid compositions are liquid solutions, which can be used for treating aqueous solutions, surfaces and objects. Some are approved for food contact surfaces and for sanitization of some food products. Some are also registered as disinfectants or sterilants as vapor phase treatments. Examples of such products, methods for their use and descriptions of the mechanisms whereby they kill microbes are found extensively in the scientific literature and in the patented prior art.
While PAA is known to be an effective sporicide and virucide, it is also corrosive and a strong oxidizer and it can be hazardous to handle. HP is effective as a bactericide and virucide; however, it is also a strong oxidizer. Accordingly, such highly reactive materials are also difficult to store for long periods of time, e.g., many months or years. Trace amounts of impurities, especially metals, can react with the HP and the PAA and cause decomposition. Therefore, many peroxide/peracid compositions include anti-corrosive and stabilizing ingredients. In many examples, these are surfactants that coat surfaces, or that sequester metals and metal-containing impurity materials. Because HP and PAA have an equilibrium reaction that includes acetic acid, the use of buffering materials and the addition of acetic acid to such compositions is commonplace.
Some of the peroxide and peroxide/peracid containing compositions are also known to act as photosensitizers. The application of such compositions onto a surface or object, or as an aerosol cloud, followed by illumination, especially by an intense ultraviolet (UV) light, can result in very rapid microbicidal action, as has been described in the prior art. Also described are commercial products that have been found to be photosensitizers. Two examples are Zerotol™ and Rennalin™. Still others are mixtures of peroxycarboxylic acids.
Photosensitized decontamination, disinfection and sterilization offer rapid treatment, may permit a low application volume of the composition (which means lower logistical requirements for the treatment), and multiple kill mechanisms.
In spite of more than a half century of development of peroxide and peracid compositions, the prior art does not describe compositions that have outstanding ME, very low corrosivity, compatibility with a large variety of materials to be disinfected or sterilized, and that are excellent for use in photosensitized decontamination or disinfection with concomitant irreversible nucleic acid destruction or sterilization.
The object of the present invention is a peroxide/peracid composition that solves one or more of the above-identified problems.